In the motor-driven throttle valve controller described in the Japanese Patent Application Laid-Open No. 9-317538, the overshoot and the delay of the attainment time to the target opening are improved by comparing the rate of change of the opening of the throttle valve with the standard rate of change, determining whether it is in the overshoot cause area or in the settling delay area, and correcting the control gain of each term (proportion term, integration term, and differentiation term) of PID in the control duty arithmetic expression for controlling the opening even if there is the change in the environmental temperature.
Further, in the Japanese Patent Application Laid-Open No. 8-303285, the feedback control is done to decrease the deviation between the electric currents by detecting the electric current which flows to the direct current motor for driving the throttle valve, and comparing the current value with the target current value of the motor. The overshoot and the delay of the attainment time to the target opening can be cancelled to some degree in such prior art. However, the standard rate of change to judge whether it is in the overshoot cause area or in the settling delay area is different according to an individual motor in the former case. Further, this is different according to the control characteristic of the throttle opening control.
Therefore, it is necessary to determine the standard rate of change peculiar to each product, and work is bad.
A concrete solution is not described though there is the description with the idea of the addition of the correction to the control of the DC motor according to the change in an environmental temperature by measuring the change in an environmental temperature by the temperature sensor.
Further, the mechanical response delay of the motor might cause the hunting of control system in the latter case.